If using one microphone is great, two must be twice as good, right? Sometimes. 🙂

Some of the best acoustic guitar tones I’ve ever gotten have been with two microphones, this is sometimes referred to as stereo mic placement (although two microphones doesn’t always mean it’s technically “stereo,” but that’s for another day).

As with most things, if there stands to be a bigger benefit (better guitar tone), there are also greater risks (phase issues).

Stereo Width

One of the main reasons to use some sort of stereo mic technique is to capture a much wider signal. Rather than a guitar sound that’s fairly one-dimensional, using two microphones lets you capture more realistic, wide-sounding guitar. This is especially good for songs that have very little instrumentation. Full band productions typically don’t benefit from stereo-mic’d acoustic guitar, mainly because you just can’t hear it in the mix.

There are lots of ways to stereo-mic acoustic guitar — XY, Blumlein, Mid-Side, ORTF, Spaced Pair — to name a few. Each of these has its own benefit and drawbacks, and some have a “wider” sound than others. They all, however, give a wider, more realistic sound to the guitar. Think about it, we listen with two ears, it makes sense that two microphones would capture a more realistic sound.

Phase Issues

Whenever you use more than one microphone on a source, you introduce the issue of phasing. Simply put, when a single signal reaches two microphones at different points in time, the resulting sound can be thin or hollow. The slight difference in time (or phase) causes certain frequencies to cancel out.

The key to this is two-fold. First, observe the 3:1 Rule. If the microphones are too close together, phasing WILL happen…and you’ll wish you had just stuck with one microphone.

The second way to combat this is to listen in mono. When you’re placing the microphones, listen to them in mono, NOT stereo. Stereo will sound awesome, but it won’t let you know if there are any phase issues. Listening in mono will quickly point out any problems. If the signal sounds thin, or maybe even boomy, or boxy, or hollow, try moving one of the microphones a few inches. Listen as you move it. Once it sounds good again, THAT’S your placement.

So, what do you think? Leave a comment below and let us know if you stereo-mic acoustic guitar (and why).

If you want to learn all about recording acoustic guitar, join me for the 4-week class, starting this Thursday. Limited spaces available. Click here to check it out.

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  • That’s fine, but it’s not the same as a stereo-mic’d acoustic. Sometimes double-tracking doesn’t work for the song.

  • Cruzazul_boyo

    Is It bad to mic it stereo then do the Hard L-R panning, followed by a slight 15ms shift on one of the tracks? Or even just to record one track with one mic and do a duplicate of the above mentioned, just with a slight eq diff?

    • There’s nothing “wrong” with it, but the whole point of stereo-mic is to get a great sounding stereo signal. Shifting one of them 15 ms creates all sorts of phase issues, as if you did a crappy job placing the mics. If the image isn’t wide enough, try a different mic technique. Or double-track the guitar.

  • If you’re tracking lots of overlays for a really thick sound, I find that actually stereo mic’ing just gets too phasey, multiple guitars recorded in mono seem to sit better in the mix.
     However, if you want a really chunky guitar sound with one or two acoustics, then stereo is the way to go. You get a lot more control over the sound, and a lot more options in mixing. 

  • Frank Adrian

    I’m fairly leery about miking individual instruments in stereo. People don’t do it that often and usually don’t get the experience to do it well. Unless the arrangement is particularly sparse and you want to center the mix around the stereo-miked instrument, you’re better off not doing it.

    Mixing a stereo image into a sound field can be difficult. If one is not careful, one can end up with an instrument that sounds smeared instead of wide or an instrument that sounds abnormally wide (not many guitars are ten feet across). In addition, stereo miking can make the positioning of the instrument harder in the sound field without adding widening/lopsidedness artifacts. With a stereo source, where you are is what you get (for the most part).

    One thing that wasn’t mentioned in the article was the importance of microphone distance from the sound source whenever stereo-miking. In general, the further the mikes can be while still picking up the sound source well, the more natural the instrument will feel in the sound field.

    In general, rather than stereo miking, I tend to use a close mike and use a stereo pair of room mikes. I can then easily localize the main instrument using the close mike and then add width using the room mikes. It’s a lot more forgiving at the mix stage than a straight stereo mike arrangement.